Stretching-resistant aluminum plastic film, preparation method thereof and lithium battery

Abstract

The invention belongs to the technical field of aluminum plastic films, and particularly relates to a tensile aluminum plastic film, a preparation method thereof and a lithium battery, the tensile aluminum plastic film comprises a PA composite film layer, an adhesive layer, an aluminum foil layer and a CPP film layer from outside to inside in sequence; the PA composite film layer is prepared by compounding 90-98 parts by mass of PA, 1-5 parts by mass of a foaming agent and 1-5 parts by mass of a nucleating agent; according to the tensile aluminum-plastic film, the preparation method thereof and the lithium battery, the foaming agent is added into the PA matrix for microcellular foaming and is matched with the nucleating agent to form a good three-dimensional pore structure, nucleation sites are provided for small bubbles, and foam pores are distributed more uniformly, so that the tensile property of the aluminum-plastic film is improved, meanwhile, the weight of the material is also reduced, and the service life of the material is prolonged. Therefore, the material has higher toughness, impact strength and dimensional accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum-plastic films, and in particular relates to an anti-stretching aluminum-plastic film and a preparation method thereof, and a lithium battery. Background Art

[0002] Lithium battery soft packaging is becoming more and more widely used due to its advantages such as light weight and high safety. Its main structure is composed of a protective layer, an aluminum foil layer and a heat-sealing layer. Usually, the protective layer is a nylon (PA) film, and the heat-sealing layer is a cast polypropylene (CPP). PA material is widely used as the outer protective layer material of lithium-ion battery packaging materials because of its excellent properties such as high mechanical strength, low friction coefficient, good self-lubrication, and high softening point. As a protective layer of aluminum-plastic film, PA has the ability to share the load of aluminum foil, but the mechanical strength of PA is limited, making it difficult to improve the tensile strength and deep punching strength of the aluminum-plastic film, and it still needs to be improved.

[0003] Therefore, how to overcome the defect of insufficient stretch resistance of PA film is a technical problem that needs to be solved urgently in this field.

[0004] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0005] The embodiments of the present disclosure at least provide a stretch-resistant aluminum-plastic film and a preparation method thereof, and a lithium battery.

[0006] In the first aspect, an embodiment of the present disclosure provides a stretch-resistant aluminum-plastic film, which includes, from the outside to the inside, a PA composite film layer, an adhesive layer, an aluminum foil layer and a CPP film layer; the PA composite film layer is made of 90-98 parts of PA, 1-5 parts of a foaming agent and 1-5 parts of a nucleating agent by mass.

[0007] In an optional embodiment, the foaming agent includes any one or more combinations of azodicarbonamide, calcium carbonate, magnesium carbonate, sodium bicarbonate, sulfonyl hydrazide and supercritical carbon dioxide.

[0008] In an optional embodiment, the nucleating agent includes any one or more combinations of nanosponge cyclodextrin oligomers, carbon black, graphite and hydrotalcite.

[0009] In an optional embodiment, the PA composite film has a thickness of 15-30 μm.

[0010] In an optional embodiment, the adhesive layer is a two-component polyurethane adhesive layer with a thickness of 2-5 μm; wherein the first polyurethane adhesive comprises polyurethane glue; and the second polyurethane adhesive comprises a polyurethane curing agent.

[0011] In an optional embodiment, the thickness of the aluminum foil layer is 35-55 μm.

[0012] In an optional embodiment, the thickness of the CPP film layer is 30-60 μm.

[0013] In a second aspect, the embodiments of the present disclosure also provide a method for preparing the stretch-resistant aluminum-plastic film as described above, comprising the following steps: step S1, mixing PA, a foaming agent and a nucleating agent in proportion, performing microporous foaming and adjusting the thickness, and winding the film by traction to obtain a PA composite film; step S2, coating an acid-resistant agent on both sides of the aluminum foil layer to form an acid-resistant film; step S3, coating and bonding the matte surface of the aluminum foil forming the acid-resistant film to the PA composite film with polyurethane glue, and forming an adhesive layer on the bonding surface; step S4, hot-pressing and bonding the bright surface of the aluminum foil forming the acid-resistant film to the CPP film with polyurethane glue to obtain a stretch-resistant aluminum-plastic film.

[0014] In an optional embodiment, the microporous foaming in step S1 specifically includes: the foaming agent includes any one or more combinations of azodicarbonamide, calcium carbonate, magnesium carbonate, sodium bicarbonate, sulfonyl hydrazide and supercritical carbon dioxide; the nucleating agent includes any one or more combinations of nanosponge cyclodextrin oligomers, carbon black, graphite and hydrotalcite; and the processing temperature of the microporous foaming is 200-240°C.

[0015] In a third aspect, the embodiments of the present disclosure further provide a lithium battery, which is composed of a protective layer, an aluminum foil layer and a heat-sealing layer, wherein the aluminum foil layer is made of the aforementioned anti-stretching aluminum-plastic film.

[0016] The beneficial effects of the present invention are that the stretch-resistant aluminum-plastic film and its preparation method, and the lithium battery are prepared by adding a foaming agent to a PA matrix for microporous foaming, and a nucleating agent is used to form a good three-dimensional pore structure, so as to provide nucleation sites for small bubbles and make the pore distribution more uniform, thereby improving the stretch resistance of the aluminum-plastic film, and at the same time reducing the weight of the material, so that the material has higher toughness, impact strength and dimensional accuracy.

[0017] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic structural diagram of a stretch-resistant aluminum-plastic film provided in an embodiment of the present disclosure.

[0021] In the figure:

[0022] 1. PA composite film layer; 2. Adhesive layer; 3. Aluminum foil layer; 4. CPP film layer. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0025] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0026] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0027] Glossary:

[0028] In this article, PA is polyamide, commonly known as nylon; NS is the abbreviation of nanosponge cyclodextrin oligomer; the main component of foaming agent AC is azodicarbonamide.

[0029] The microporous foaming process can generate a large number of micropores inside the polymer matrix, forming a unique dense surface and core foaming structure. This structure can further reduce the weight of the material, making the material have higher toughness, impact strength and dimensional accuracy, which is of great significance to the requirements of lightweighting. Adding particles to the matrix can provide higher toughness, good energy absorption, and improve fatigue life. At the same time, the smaller and denser cell structure enhances the above advantages, making the foamed composite material have better comprehensive mechanical properties.

[0030] Adding foaming agent to PA matrix can improve the load-bearing capacity and mechanical properties, slow down the rapid growth of cracks, and transform the fracture in PA foam composite materials from single matrix fracture to composite fracture of matrix fracture and cell fracture, which helps to improve mechanical toughness.

[0031] The defects existing in the above solutions are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present disclosure for the above problems below should be the contributions made by the inventor to the present disclosure during the disclosure process.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0033] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0034] The embodiment of the present disclosure provides a stretch-resistant aluminum-plastic film, which includes, from the outside to the inside, a PA composite film layer, an adhesive layer, an aluminum foil layer and a CPP film layer; the PA composite film layer is made of 90-98 parts of PA, 1-5 parts of a foaming agent and 1-5 parts of a nucleating agent by weight.

[0035] In some embodiments, specifically, the foaming agent includes any one or more combinations of azodicarbonamide, calcium carbonate, magnesium carbonate, sodium bicarbonate, sulfonyl hydrazide and supercritical carbon dioxide, preferably azodicarbonamide.

[0036] In some embodiments, specifically, the nucleating agent includes any one or more combinations of nanosponge cyclodextrin oligomers, carbon black, graphite, and hydrotalcite, preferably nanosponge cyclodextrin oligomers.

[0037] In some embodiments, specifically, the thickness of the PA composite film is 15-30 μm.

[0038] In some embodiments, specifically, the adhesive layer is a two-component polyurethane adhesive layer with a thickness of 2-5 μm; wherein the first polyurethane adhesive comprises polyurethane glue; and the second polyurethane adhesive comprises a polyurethane curing agent.

[0039] In some embodiments, specifically, the thickness of the aluminum foil layer is 35-55 μm.

[0040] In some embodiments, specifically, the thickness of the CPP film layer is 30-60 μm.

[0041] The disclosed embodiment also provides a method for preparing the stretch-resistant aluminum-plastic film as described above, comprising the following steps: step S1, mixing PA, a foaming agent and a nucleating agent in proportion, performing microporous foaming and adjusting the thickness, and rolling the film into a PA composite film by traction; step S2, coating an acid-resistant agent on both sides of the aluminum foil layer to form an acid-resistant film; step S3, coating and bonding the matte surface of the aluminum foil forming the acid-resistant film to the PA composite film with polyurethane glue, and forming an adhesive layer on the bonding surface; step S4, hot-pressing and bonding the bright surface of the aluminum foil forming the acid-resistant film to the CPP film with polyurethane glue to obtain the stretch-resistant aluminum-plastic film.

[0042] In some embodiments, specifically, the microporous foaming in step S1 specifically includes: the foaming agent includes any one or more combinations of azodicarbonamide, calcium carbonate, magnesium carbonate, sodium bicarbonate, sulfonylhydrazide and supercritical carbon dioxide; the nucleating agent includes any one or more combinations of nanosponge cyclodextrin oligomers, carbon black, graphite and hydrotalcite; and the processing temperature of the microporous foaming is 200-240°C.

[0043] In some embodiments, specifically, in step S3, the lamination pressure is 0.3-0.5 MPa, the lamination temperature is 60-80° C., the oven temperature is 70-90° C., and the speed is 60 m / min.

[0044] In some embodiments, specifically, in step S4, the lamination pressure is 0.3-0.5 MPa, the lamination temperature is 160-180° C., the oven temperature is 200-240° C., and the speed is 30 m / min.

[0045] The disclosed embodiment also provides a lithium battery, which is composed of a protective layer, an aluminum foil layer and a heat-sealing layer. The aluminum foil layer adopts the above-mentioned tensile-resistant aluminum-plastic film.

[0046] The performance of the aluminum-plastic film provided by the present invention is tested according to the following method:

[0047] (1) Tensile strength

[0048] The tensile strength was tested using Shimadzu AGS-X series electronic universal testing machine.

[0049] (2) Deep pit

[0050] Punch holes with a shell punching machine. Start punching from 5.0mm, punch 10 samples continuously, check under strong light for no delamination, cracks, or pinholes, then increase by 0.3mm and continue punching for 10 more until it breaks. Record the punching depth before breakage as the limit punching depth.

[0051] (3) Heat sealing strength of aluminum-plastic film

[0052] Using the Japanese Tester Sangyo TP-701-B heat sealer, two pieces of 10×10cm-2 aluminum-plastic film were heat-sealed to the heat seal layer at a heat seal temperature of 190°C, a pressure of 0.5MPa, and a heat seal time of 3s. After the sample cooled to room temperature, the heat seal strength was tested using the Shimadzu AGS-X series electronic universal testing machine.

[0053] (4) Warping

[0054] Cut the sample into 10×10 cm -2 Lay the sheet flat on the table, use a ruler to measure the highest curled surface, and record the value.

[0055] Example 1

[0056] The invention provides an aluminum-plastic film with good stretchability and a preparation method thereof.

[0057] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0058] A PA composite material was obtained by uniformly mixing 98 parts of PA resin, 1 part of foaming agent AC, and 1 part of nucleating agent carbon black.

[0059] The composite material is put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C, and co-extruded through a T-die at a casting speed of 50 m / min. The film is cooled and crystallized, and the thickness is measured and adjusted to 25 μm. The film is then pulled and rolled to obtain a PA composite foam film.

[0060] The matte surface of the aluminum foil that has been passivated is coated and laminated with the above PA composite foam film using polyurethane glue. The glue thickness is 3μm, the pressure is 0.4MPa, the lamination temperature is 70℃, the oven temperature is 80℃, and the speed is 60m / min. After traction and reeling, it is ready for use.

[0061] The bright side of the aluminum foil in the aluminum foil-laminated PA composite foam film semi-finished product was hot-pressed with a 45 μm CPP film, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a laminating temperature of 170° C., an oven temperature of 220° C., and a speed of 30 m / min to obtain the final product.

[0062] Example 2

[0063] As provided in Example 1, an aluminum-plastic film with good stretchability and a preparation method thereof.

[0064] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0065] A PA composite material was obtained by uniformly mixing 94 parts of PA resin, 3 parts of foaming agent AC, and 3 parts of nucleating agent carbon black.

[0066] The composite material is put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C, and co-extruded through a T-die at a casting speed of 50 m / min. The film is cooled and crystallized, and the thickness is measured and adjusted to 25 μm. The film is then pulled and rolled to obtain a PA composite foam film.

[0067] The matte surface of the aluminum foil that has been passivated is coated and laminated with the above PA composite foam film using polyurethane glue. The glue thickness is 3μm, the pressure is 0.4MPa, the lamination temperature is 70℃, the oven temperature is 80℃, and the speed is 60m / min. After traction and reeling, it is ready for use.

[0068] The bright side of the aluminum foil in the aluminum foil-laminated PA composite foam film semi-finished product was hot-pressed with a 45 μm CPP film, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a laminating temperature of 170° C., an oven temperature of 220° C., and a speed of 30 m / min to obtain the final product.

[0069] Example 3

[0070] As provided in Example 1, an aluminum-plastic film with good stretchability and a preparation method thereof.

[0071] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0072] A PA composite material was obtained by uniformly mixing 90 parts of PA resin, 5 parts of foaming agent AC and 5 parts of nucleating agent carbon black.

[0073] The composite material is put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C, and co-extruded through a T-die at a casting speed of 50 m / min. The film is cooled and crystallized, and the thickness is measured and adjusted to 25 μm. The film is then pulled and rolled to obtain a PA composite foam film.

[0074] The matte surface of the passivated aluminum foil and the PA composite foam film are coated with polyurethane glue, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a lamination temperature of 70°C, an oven temperature of 80°C, and a speed of 60 m / min. The film is then rolled up for later use.

[0075] The bright side of the aluminum foil in the aluminum foil-laminated PA composite foam film semi-finished product was hot-pressed with a 45 μm CPP film, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a laminating temperature of 170° C., an oven temperature of 220° C., and a speed of 30 m / min to obtain the final product.

[0076] Example 4

[0077] As provided in Example 1, an aluminum-plastic film with good stretchability and a preparation method thereof.

[0078] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0079] A PA composite material was obtained by uniformly mixing 98 parts of PA resin, 1 part of foaming agent AC and 1 part of nucleating agent NS.

[0080] The preparation method of the nucleating agent NS of this embodiment comprises:

[0081] At room temperature, β-cyclodextrin (200 g) was dissolved in 300 mL of dimethyl sulfoxide. 75 g of diphenyl carbonate was added, the solution was heated to 90 ° C, magnetically stirred, and the reaction was carried out for 4 hours. As the reaction proceeded, the viscosity of the reaction system increased, and a colloidal product was obtained, which was marked as NS. The product was washed with a large amount of ethanol and extracted with hot ethanol Soxhlet for 16 hours to remove unreacted diphenyl carbonate and phenol. Finally, the solid was ground into powder and dried in a vacuum at 60 ° C.

[0082] The composite material is put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C, and co-extruded through a T-die at a casting speed of 50 m / min. The film is cooled and crystallized, and the thickness is measured and adjusted to 25 μm. The film is then pulled and rolled to obtain a PA composite foam film.

[0083] The matte surface of the passivated aluminum foil and the PA composite foam film are coated with polyurethane glue, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a lamination temperature of 70°C, an oven temperature of 80°C, and a speed of 60 m / min. The film is then rolled up for later use.

[0084] The bright side of the aluminum foil in the aluminum foil-laminated PA composite foam film semi-finished product was hot-pressed with the 45 μm CPP film, with the glue thickness of 3 μm, the pressure of 0.4 MPa, the laminating temperature of 170° C., the oven temperature of 220° C., and the speed of 30 m / min to obtain the final product.

[0085] Example 5

[0086] As provided in Example 1, an aluminum-plastic film with good stretchability and a preparation method thereof.

[0087] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0088] 94 parts of PA resin, 3 parts of foaming agent AC and 3 parts of nucleating agent NS were uniformly mixed to obtain a PA composite material.

[0089] The preparation method of the nucleating agent NS of this embodiment comprises:

[0090] At room temperature, β-cyclodextrin (200 g) was dissolved in 300 mL of dimethyl sulfoxide. 75 g of diphenyl carbonate was added, the solution was heated to 90 ° C, magnetically stirred, and the reaction was carried out for 4 hours. As the reaction proceeded, the viscosity of the reaction system increased, and a colloidal product was obtained, which was marked as NS. The product was washed with a large amount of ethanol and extracted with hot ethanol Soxhlet for 16 hours to remove unreacted diphenyl carbonate and phenol. Finally, the solid was ground into powder and dried in a vacuum at 60 ° C.

[0091] The composite material is put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C, and co-extruded through a T-die at a casting speed of 50 m / min. The film is cooled and crystallized, and the thickness is measured and adjusted to 25 μm. The film is then pulled and rolled to obtain a PA composite foam film.

[0092] The matte surface of the passivated aluminum foil and the PA composite foam film are coated with polyurethane glue, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a lamination temperature of 70°C, an oven temperature of 80°C, and a speed of 60 m / min. The film is then rolled up for later use.

[0093] The bright side of the aluminum foil in the aluminum foil-laminated PA composite foam film semi-finished product was hot-pressed with the 45 μm CPP film, with the glue thickness of 3 μm, the pressure of 0.4 MPa, the laminating temperature of 170° C., the oven temperature of 220° C., and the speed of 30 m / min to obtain the final product.

[0094] Example 6

[0095] As provided in Example 1, an aluminum-plastic film with good stretchability and a preparation method thereof.

[0096] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0097] 90 parts of PA resin, 5 parts of foaming agent AC and 5 parts of nucleating agent NS were uniformly mixed to obtain a PA composite material.

[0098] The preparation method of the nucleating agent NS of this embodiment comprises:

[0099] At room temperature, β-cyclodextrin (200 g) was dissolved in 300 mL of dimethyl sulfoxide. 75 g of diphenyl carbonate was added, the solution was heated to 90 ° C, magnetically stirred, and the reaction was carried out for 4 hours. As the reaction proceeded, the viscosity of the reaction system increased, and a colloidal product was obtained, which was marked as NS. The product was washed with a large amount of ethanol and extracted with hot ethanol Soxhlet for 16 hours to remove unreacted diphenyl carbonate and phenol. Finally, the solid was ground into powder and dried in a vacuum at 60 ° C.

[0100] The composite material is put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C, and co-extruded through a T-die at a casting speed of 50 m / min. The film is cooled and crystallized, and the thickness is measured and adjusted to 25 μm. The film is then pulled and rolled to obtain a PA composite foam film.

[0101] The matte surface of the passivated aluminum foil and the PA composite foam film are coated with polyurethane glue, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a lamination temperature of 70°C, an oven temperature of 80°C, and a speed of 60 m / min. The film is then rolled up for later use.

[0102] The bright side of the aluminum foil in the aluminum foil-laminated PA composite foam film semi-finished product was hot-pressed with a 45 μm CPP film, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a laminating temperature of 170° C., an oven temperature of 220° C., and a speed of 30 m / min to obtain the final product.

[0103] Comparative Example 1

[0104] Provided are an aluminum-plastic film with good stretchability and a preparation method thereof.

[0105] The aluminum foil with a thickness of 45 μm is coated on both sides with the passivation liquid to form an acid-resistant film, dried in an oven at 240°C, and rolled up for use.

[0106] 100 parts of PA resin were put into an extruder, a filter, a transmission pipeline, a distributor, and a T-die for pressurized melting and plasticization at a temperature of 240°C. The resin was co-extruded through a T-die at a casting speed of 50 m / min. The resin was cooled and crystallized into a film. The thickness was measured and adjusted to 25 μm. The film was then pulled and rolled to obtain a PA film.

[0107] The matte surface of the passivated aluminum foil is coated and laminated with the PA film using polyurethane glue, with a glue thickness of 3 μm, a pressure of 0.4 MPa, a lamination temperature of 70°C, an oven temperature of 80°C, and a speed of 60 m / min. The film is then rolled up for later use.

[0108] The bright side of the aluminum foil in the aluminum foil-PA film semi-finished product is hot-pressed with the 45 μm CPP film, with the glue thickness of 3 μm, the pressure of 0.4 MPa, the pressing temperature of 170° C., the oven temperature of 220° C., and the speed of 30 m / min to obtain the final product.

[0109] Table 1 Performance test results of aluminum-plastic films of Examples 1-6 and Comparative Example 1

[0110]

[0111] Specifically, the tensile strength and the maximum crater depth of Comparative Example 1 in which no foaming agent and nucleating agent are added are not as good as those of the embodiment, and the warping problem is serious, which shows that adding a foaming agent to the PA matrix in the embodiment can improve the bearing capacity and mechanical properties, delay the rapid growth of cracks, and transform the fracture in the PA foam composite material from a single matrix fracture to a composite fracture of matrix fracture and cell fracture, which helps to improve the mechanical toughness.

[0112] In summary, the present stretch-resistant aluminum-plastic film and its preparation method, and the lithium battery are prepared by adding a foaming agent to the PA matrix for microporous foaming, and a nucleating agent is used to form a good three-dimensional pore structure, which provides nucleation sites for small bubbles and makes the pore distribution more uniform, thereby improving the tensile resistance of the aluminum-plastic film, while also reducing the weight of the material, so that the material has higher toughness, impact strength and dimensional accuracy.

[0113] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A tensile aluminum-plastic film, characterized in that: From outside to inside, it includes: PA composite film layer, adhesive layer, aluminum foil layer and CPP film layer; The PA composite film layer is prepared by compounding 90-98 parts of PA, 1-5 parts of foaming agent and 1-5 parts of nucleating agent by weight.

2. The stretch-resistant aluminum-plastic film according to claim 1, characterized in that: The foaming agent includes any one or more combinations of azodicarbonamide, calcium carbonate, magnesium carbonate, sodium bicarbonate, sulfonyl hydrazide and supercritical carbon dioxide.

3. The stretch-resistant aluminum-plastic film according to claim 1, characterized in that: The nucleating agent includes any one or more combinations of nanosponge cyclodextrin oligomer, carbon black, graphite and hydrotalcite.

4. The stretch-resistant aluminum-plastic film according to claim 1, characterized in that: The thickness of the PA composite film is 15-30 μm.

5. The stretch-resistant aluminum-plastic film according to claim 1, characterized in that: The adhesive layer is a two-component polyurethane adhesive layer with a thickness of 2-5 μm; The first polyurethane adhesive includes polyurethane glue; The second polyurethane adhesive includes a polyurethane curing agent.

6. The stretch-resistant aluminum-plastic film according to claim 1, characterized in that: The thickness of the aluminum foil layer is 35-55 μm.

7. The stretch-resistant aluminum-plastic film according to claim 1, characterized in that: The thickness of the CPP film layer is 30-60 μm.

8. A method for preparing a tensile-resistant aluminum-plastic film according to any one of claims 1 to 7, characterized in that: The steps include: Step S1, PA, a foaming agent and a nucleating agent are mixed in proportion, microporous foaming is performed and the thickness is adjusted, and the film is rolled up by traction to obtain a PA composite film; Step S2, coating an acid-resistant agent on both sides of the aluminum foil layer to form an acid-resistant film; Step S3, coating and laminating the matte surface of the aluminum foil formed with the acid-resistant film and the PA composite film with polyurethane glue to form an adhesive layer on the laminating surfaces; Step S4, hot pressing and laminating the bright surface of the aluminum foil formed with the acid-resistant film to the CPP film using polyurethane glue to obtain a tensile-resistant aluminum-plastic film.

9. The preparation method according to claim 8, characterized in that: The microcellular foaming in step S1 specifically includes: The foaming agent includes any one or more combinations of azodicarbonamide, calcium carbonate, magnesium carbonate, sodium bicarbonate, sulfonyl hydrazide and supercritical carbon dioxide; The nucleating agent includes any one or more combinations of nanosponge cyclodextrin oligomer, carbon black, graphite and hydrotalcite; and The processing temperature of the microcellular foaming is 200-240°C.

10. A lithium battery, composed of a protective layer, an aluminum foil layer and a heat-sealing layer, characterized in that: The aluminum foil layer is the stretch-resistant aluminum-plastic film as described in any one of claims 1 to 7.

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